AbstractOil palm is one of the world’s most rapidly expanding crops, replacing humid forests across tropical regions. Studies examining the effect of this land conversion on biodiversity have tended to focus predominantly on Southeast Asia, where the majority of the world’s oil palm is produced. Because the Amazon possesses the greatest area of suitable land for oil palm expansion, oil palm is considered an emerging threat to Amazonian biodiversity. This is the first study to examine how oil palm agriculture affects avian diversity within the context of Western Amazonia. We used mist nets to conduct avifaunal surveys of forest and oil palm habitat in the Pucallpa region of Peruvian Amazonia. Bird species richness, species evenness, and overall abundance were all significantly higher in the forest than in oil palm habitat. Strikingly, less than 5% of all captured species were common to both forest and oil palm habitat. The species absent from the oil palm plantations were disproportionately habitat specialists, forest interior birds, birds with high sensitivity to disturbance, and insectivores and frugivores. The results suggest that oil palm is particularly poor habitat for Amazonian birds, and that the species that are persist on them are of lower conservation value. Given the apparent lack of diversity on oil palm plantations, preventing further conversion of forests to oil palm should be prioritized.